The U.S. Food and Drug Administration has approved Tregzi, a novel donor-cell therapy designed to protect adults with blood cancers from chronic graft-versus-host disease, one of the most serious complications after stem cell transplantation. The treatment uses specialized regulatory T-cells from a matched donor to help rebuild the patient’s immune system. In the pivotal PRECISION-T trial, 78% of patients who received Tregzi achieved chronic GVHD-free survival at one year, compared with just 38.4% of patients who received a standard transplant approach. This represents a major advance in making stem cell transplantation safer for patients battling leukemia, lymphoma, and related blood cancers. The approval marks a meaningful step toward immune-system protection and recovery in cancer care.